correlation of brain and thenar muscle oximetry during cardiac surgery with parameters of acute kidney injury

Conditions: Acute Kidney Injury; Heart Valve Diseases

Summary: identification of risk factors of acute kidney injury (aki). it is hypothesized that there might be a correlation between brain oximetry, tissue saturation of thenar muscle and marker of aki in blood - neutrophil gelatinase-associated lipocalin (ngal) - measured in blood samples during the first post-op day.

the day before operation, after verification of inclusion and exclusion criteria, the visiting anesthesiologist will explain to the patient the aim of the study. by signing an informed consent the patient will be recruited into the study. on the evening before operation the patient will receive the statin in a dose taken along. in the or the anesthesiologist will verify if creatinin and blood urea nitrogen were measured the day before operation - if not, a blood sample for the test will be obtained and sent to perform the tests. before induction of anesthesia a bi-spectral index (bis) probe will be placed on the patients forehead. above the bis probe a invos(tm) probe for brain oximetry (5100 c cerebral/somatic oximeter, somanetics, medtronic) will be placed. brain oximetry by near infrared saturation (nirs) and tissue saturation on thenar muscle will be recorded before and during operation on nine timepoints. as nirs and thenar muscle saturation are non-routine non-invasive methods of intraoperative monitoring, patient had to sign an informed consent to participate into the study, and ethic committee approval for the study protocol was appealed and granted. general anesthesia will be induced by: fentanyl 0.2 mg, propofol 0.5-1.5 mg/kg in bolus 200ml/godz.; and rocuronium - 0.5 mg/kg. after induction dexamethasone will be given in a dose of 0,7-1 mg/kg. for conduction of anesthesia before cardiopulmonary bypass (cpb) sevoflurane will be added to the inhaled mixture of air and oxygen. on cpb propofol will be given iv. in case of hemodynamic instability after commencing cpb, which will require catecholamines in a cumulative dose of \> 1.5 standard, or in case of trouble to commence cpb, propofol will be replaced by midazolam in a dose 0.2-0.3 mg/kg/hour. during anesthesia, first post-operative day and hospital stay a total of 278 variables will be recorded: hemodynamic parameters, iv fluid doses, inotropes, vasopressors, diuretics, urine output, transfusions, etc.

Eligibility criteria:
inclusion criteria: * adult patients * signed informed consent * scheduled for elective on-bypass cardiac surgery (aortic valve surgery, mitral valve surgery with/without tricuspid valve surgery, ascending aorta surgery with/without aortic valve surgery). exclusion criteria: * chronic kidney insufficiency (serum creatinine \>2 mg/dl) * active infection (i.e.: endocarditis) * shock or tissue hypoperfusion before operation (blood lactate \>3 mmol/l) * left ventricle ejection fraction \<25% * vancomycin used for infection prophylaxis (i.e.: in immunosuppressed patients) * history of ischaemic shock

Keywords: acute kidney injury cardiopulmonary bypass neutrophil gelatinase-associated lipocalin tissue hypoxia